As is known, the use of optical fiber as a transmission media is growing at an accelerating rate, including within the information handling system (computer) industry. The advantages of optical fibers over other forms of transmission media are well known. The potential bandwidth (or message carrying capacity) of optical fibers is extremely high. Systems using optical fibers are resistant to electro-magnetic interference which sometimes plagues systems having electrical cables. In addition, optical fiber cabling offers a higher degree of data security than such electrical cables, as it is more difficult for unauthorized personnel to tap or access an optical fiber cable without being detected.
Optical fiber devices use single or multiple strands of fibers each having an inner circular glass core coated with an circumferential cladding having a different index of refraction. Light is transmitted along the core and totally reflected from the interface between the core and cladding. Such devices can be used as transmission lines for transmitting and/or receiving, information bearing light energy.
Typically, transmission lines terminate in optical fiber connectors, such as those referred to in the industry as SC connectors, each of which include as part thereof an outer housing wherein there is positioned the terminating end of the optical fiber. This terminating end is fixed within a ferrule, typically of ceramic material, the ferrule being resiliently oriented such that is can be slightly compressed when the connector is located within a receiving module assembly or the like. Such connectors are illustrated and described in U.S. Pat. No. 4,953,929, and in the aforementioned copending application Ser. No. 07/874,162, both of which are incorporated herein by reference. Attention is also particularly directed to U.S. Pat. No. 5,005,939, wherein an optoelectronic assembly designed to receive a duplex optical fiber connector is defined in detail, said patent also incorporated herein by reference. By the term module as used herein is meant to include an assembly as defined in 5,005,939, while the term connector is meant to include those such as the aforementioned SC type (including when same are retained in a suitable, accommodating adapter as defined in 4,953,929) as well as those of the duplex variety wherein two optical fiber terminal ends (and ferrules) are retained within a singular, common housing (one such example illustrated and described in 5,005,939).
There presently exist in the industry various coupling devices which are designed for coupling in an end-to-end orientation optoelectronic assemblies or modules with associated optical fiber connectors. Due to manufacturing tolerances, however, precision alignment between such structures is often difficult. The connector assembly as defined in Ser. No. 07/874,162 is designed to overcome many such tolerance problems, primarily when attempting to mate two individual SC-type connectors with a singular module, by enabling a degree of flexibility of movement of various parts during connector insertion within a receiving coupling device (shroud). Similarly, the adapter defined in 4,953,929 enables relative movement of the two contained connectors during such insertion. Clearly, both of these structures overcome many of the tolerance problems associated with rigidly fixed embodiments such as known duplex connectors having a singular housing with two encased ferrules.
As defined herein, the present invention provides a new and unique coupling device for optically coupling an optoelectronic module (or assembly) with a mating optical fiber connector such that precision alignment between the connector's optical ferrule(s) and the optoelectronic device (s) retained within the module is attained. Such optoelectronic devices are also often referred to in the industry as optical transceivers, functioning in the manner described in detail in 5,005,939. As understood, the coupling device of the invention is able to substitute for the structure referred to in 5,005,939 as a shroud, and thus may also be referred to as such a component. The invention is of course not to be limited to such usage, as the invention may be used in any situation requiring coupling between such structures as cited above.
One particular application for the invention is as part of what is referred to in the industry as an F.D.D.I. assembly, F.D.D.I. standing for Fiber Distributed Data Interface, and constituting a standard adopted in the industry and approved by the American National Standards Institute (A.N.S.I.). This standard defines the critical requirements for various optoelectronic components, including connectors and modules, which will form part of a high speed optic network. As understood from the following, the invention is able to satisfactorily meet such critical requirements, while assuring a product which is of relatively simple construction and which is also relatively inexpensive to manufacture and purchase. Further, the invention is able to overcome many of the tolerance problems mentioned above by the provision of a structure which is able to accommodate relative movement of the module's optoelectronic devices in addition to movement by the incoming optical fiber connector ends, while, surprisingly, still assuring precision alignment between such components.
It is believed that such a coupling device, particularly one suited especially for utilization within an information handling system, would represent a significant advancement in the art.